Sleep regression ages
Parents talk about sleep regressions at 4, 6, 8, 12 and 18 months and at 2 years. Research has not found a fixed timetable. Here is what is known about each age.
Do sleep regressions happen at set ages?
Sleep regression is a popular name for a stretch of worse sleep in a baby who was sleeping better before. It is not an event that research has pinned to the calendar: Cleveland Clinic notes that research has not shown regressions happening like clockwork at a specific age for every baby.
The Sleep Foundation says it is not uncommon for one to occur at around 4 months, as well as at 6, 8, 12 and 18 months. Not every baby has one at any of these ages, and many have a rough patch at some other time.
Ages parents report, and what goes with them
| Age | What is often going on |
|---|---|
| 4 months | Sleep starts to include lighter stages. The age parents report most. |
| 6 months | Night waking often returns. Separation anxiety can start. |
| 8 months | Separation anxiety, crawling and pulling up to stand. |
| 12 months | Standing and walking. Either one or two naps is normal. |
| 18 months | The move from two naps to one. Teething. |
| 2 years | Nap refusal and the move from a crib to a bed. |
These ages are what parents report, not a timetable from research. Each row says what the sources describe at around that age.
How long do sleep regressions last?
Cleveland Clinic says regressions typically last a week or two. The Sleep Foundation says that in most cases the trouble lasts a few days to a few weeks. Nobody can give you a date, and it is different for every child.
What helps at any age
- Rule out other causes first. Do not assume a sleep problem is a regression: illness, hunger and a wet diaper can look the same.
- Keep the same bedtime routine every night, in the same order.
- Keep wake-up time, naps and bedtime at about the same times every day.
- Put your baby down drowsy but awake, so they practice falling asleep in the crib.
- Feed a young baby who wakes hungry, and ask your pediatrician before you cut a night feed.
When to call the pediatrician
Talk to your pediatrician if sleep does not get back on track, if something does not seem right to you, or if you notice snoring, trouble breathing, a fever, poor weight gain or feeds that are a struggle.
Get a plan for tonight
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Related guides
Sources
- Cleveland Clinic. The 4-Month Sleep Regression: What Parents Need To Know. July 2022.
- Sleep Foundation. 4-Month Sleep Regression. Updated July 2025.
- Nemours KidsHealth. Sleep and Your Baby, by age; Naps.
- Nationwide Children's Hospital. Sleep in Infants; Sleep in Toddlers.
- Stanford Medicine Children's Health. Infant Sleep.
- Staton S, et al. Many naps, one nap, none: a systematic review and meta-analysis of napping patterns in children 0 to 12 years. Sleep Medicine Reviews, 2020.
General information for parents, not medical advice. Independent, not affiliated with the American Academy of Pediatrics or any medical body. Talk to your pediatrician about your baby's health.